Lubricating composition



Patented Oct. 31, 1944 2,361,804 LUBBICATING courosmon Chester E.Wilson, San Pedro, GaliL, assignor to Union Oil Company of California,Los Angeles, Calii., a corporation of California No Drawing.

Application February 18, 1941, Serial No. 319,439

28 Claims. (01. 252-33) This invention relates to mineral lubricatingoils which have been modified by the addition of constituents to impartto them special characteristics especially adapting them to severeserv..

ice uses such as are encountered in Diesel engines, high output aviationengines and the like.

This application'is a continuation-in-part of my copending applications,Serial No. 277,677, filed June 6, 1989, Serial No. 305,496 filedNovember 21, 1939, Serial No. 345,844 filed July 16,1940, now issued asPatent No. 2,280,419 of April 21, 1942, and Serial No. 362,009 filedOctober 16, 1940.

In Diesel and similar engines the high temperatures developed in thecylinders tend to act upon lubricating oils to cause the deposition ofresinous and varnish-like products on the pistons and elsewheretoproduce lacquer-like coatings 3% of oil-soluble metal salts of theweakly acidic non-carboxylic organic acids, said salts being capable ofreacting with acidic corrosive materials formed or present in the oilduring use to form metal salts of such corrosion products and liberatefree non-carboxylic acids which are sufilcient- 1y weak to benon-corrosive to hearings or the and carbonaceous materials which tendto cause ring and valve sticking and interfere with engine operation.Furthermore, iuel residues from incomplete combustion of fuel contributeto the deposition of lacquer-like and carbonaceous materials in theengine. Previously in aneflort to overcome these difllculties varioustypes of metal soaps of fatty acids and the like have been introducedinto the lubricating oil, and they have exhibited a detergent effect inthat they have acted to prevent such depositions. However, in general,it has been observed that in those engines fitted with certain types 01.bearings, such as cadmium-silver or copper-lead bearings, the use ofsuch fatty acid soap-compounded oils has often given rise to bearingcorrosion, such corrosion apparently being due to the formation in theoil of corrosive materials of acidic character. The formation of thesecorrosive materials may even be catalyzed by the presence of such soapsin the oil. Also, some of the metal soaps added as detergents haverequired the use of free fatty acid and the like to act as a commonsolvent to promote solutionsof the soaps in the oil, and the presence ofsuch free acidity has possibly contributed to the corrosion of alloybearings 01 the type mentioned above.

Primarily, the object of this invention is to produce for such severeservice conditions as are encountered in Diesel engines, lubricatingoils which will be non-corrosive to corrosion-sensitive bearings of thecopper-lead and cadmium-silver type and which will also avoid thedeposition of lacquer and varnish-like materials upon pistons andovercome carbon deposition behind the rings.

The present invention in one aspect resides in mineral lubricating oilscontaining small amounts in the order of about 0.5% or 0.75% up to 2% orcopper-lead and cadmium-silver alloy p Itls possible that the metalsalts of weak non-carbonylic organic acids within the scope of thisinvention which are considered as "anti-corrosion" agents also act asanti-oxidants tending to prevent thei'ormation oi. corrosive acidity.

The invention further resides in lubricating oils containingcorrespondingly small amounts of such oil-soluble anti-corrosion agentsin combination with correspondingly small amounts of other oil-solublesoaps or salts which act as "detergen agents. The detergent type soapsinclude high molecular weight oil-soluble soaps of carboxylic acidscontaining more than about 12 carbon atoms per molecule; they alsoinclude oilsoluble metal suli'onates' herein described which areespecially valuable in highly paraillnic (high viscosity index) oils.

The invention also resides in the employment of small amounts or waterin the oil composition sufllcient to insure activation of theanti-corrosion agent, either with or without respect to the presence ofa detergent soap, wherein the water content however is not suilicient toproduce gelling tendencies or interfere with the compatibility of theagents with the oil or with each other. Such a water content in thefinal product will be within a range of around two-thousandths per cent(0.002%) to two-hundredths' per cent (0.02%) or possibly a little wider.

However the invention also includes, especially for some combinationscontaining detergent soaps, the use of somewhat larger quantities orwater to activate the detergent soap and render it more efficient as adetergent. In this connection the water content appears to run betweenabout 0.05% (or perhaps as low as about 0.01% or 0.02%) and about 0.25%.In general the smaller proportions are used in oils containing soapswhich tend to gel or cloud readily. Other soaps such as the sulionatesaccept the larger proportions and can accept even more, although theadditional amounts of water do not appear to ofler any additionaladvantage. These larger proportions of water, of course, also activatethe anti-corrosion agents.

- In some instances it is desirable to have in the final product-arelatively smaller quantity oi. the

initial acidic starting material from which the salt of theanti-corrosion agent is prepared, and the invention further resides inmodified oils of this invention containing also relatively smallproportions of these free acidic materials as solubilizers orcompatibility-promotion constituents.

The term soap, which is sometimes herein used to indicate the salts ofthis invention, indicates salts of high molecular weight materialspossessing at least ten carbon atoms per molecule so as to impart gooddispersibility or solubility in the mineral lubricating oil when in theform of salts of those metals whose salts are sufllcientlyoil-dispersible or "soluble" as here required.

By the term detergent" is meant the property of removing, or materiallyretarding the accumulation of resinous, varnish-like and carbonaceousmaterials which otherwise tend to deposit upon or around piston rings orvalve stems and cause sticking thereof. The term "sulfonates" meansthose oil-soluble metal soaps which are produced from sulfonic acidsobtained from petroleum and known as "mahogany acids. and have highdetergent value, such as sodium, potassium, calcium, barium, strontiumand magnesium salts, and some heavy metal salts such as copper, zinc,aluminum, lead, nickel, cobalt, manganese, chromium, tin and iron,especially the alkaline earth metal soaps.

By the term weakly acidic non-carboxylic organic acids it is meant toinclude those noncarboxylic acidic materials having ionization constantsof about l 10-" or less, and preferably in the range of about lxlto 1 10However, in some instances it may be acceptable to use materials whoseionization constant is as high as 1x10 It may also be possible, at leastfor some uses, to employ those weakly acidic materials having ionizationconstants up to about 5 10, but in no case so far as now known can about5 1O- be exceeded; this limit safely excludes the carboxylic acids. Suchcompounds comprise the phenols, thiophenols, other enols, oximes,sulfonamides having an acidic hydrogen atom, and the like, detailedhereinafter.

Although any of the oil-soluble metal salts of the above mentionedgroups of compounds will be effective in preventing the corrosion ofbearings such as those of cadmium-silver and copper-lead alloys and willtend to prevent the deposition of carbonaceous materials in the engine,I particularly prefer to employ the oil-soluble metal salts of phenols.

By the term phenols is meant to include not only the hydroxy aromaticring compounds in which an hydroxyl group is directly attached to acarbocyclic aromatic ring, but also heterocyclic compounds in which thehydroxyl group is attached to a ring containing a sulfur, oxygen,nitrogen or other atom and in which the hydrogen of the hydroxyl groupso attached is suiliciently acidic to give the compound an ionizationconstant within the range defined above, said com pound being capable offorming an oil-soluble metal salt. It is to be further understood thatthe term "phenols includes not only monohydroxy but polyhydroxycompounds and those in which more than one ring is present, such asnaphthols and the like. In addition to the hydroxyl group or groups, thering is preferably substituted by one or more other substituents such asfor example, an alkyl group or a sulfur atom linking two phenolicradicals together such as in dipara-tertiary-amyl diphenol sulfide, theonly limits being that the compound must be noncarboxylic, and mustcontain at least one hydroxyl group of sufllcient acidity to exhibit anionization constant within the limits described above, and must form anoil-soluble metal salt. For the sake of simplicity in the followingspecification and claims, these compounds will be referred to merely asthe metal salts of phenols.

Although it is not definitely known why the metal salts of phenols actto prevent corrosion of alloy bearings and I do not wish to be bound bythe theory, it is presumed that this inhibiting power is at least inpart connected with the ability of the salts to react with the corrosiveacids formed or present in the lubricating oil, to form non-corrosivemetal salts of the corrosive acids, thereby liberating thenon-corrosive, weakly acidic phenolic compounds. As an indi-- cation ofthe manner in which the above mentioned compounds are presumed to reactto neutralize corrosive acidity, thereby rendering the oilnon-corrosive, the following exemplary equation may be given:

ical, M represents a metal, X represents the acid radical of thecorrosive acid, and H represents a replaceable or acidic hydrogen atom.

All oil-soluble metal salts of phenols, when dissolved in lubricatinoil, will tend to inhibit the corrosion of bearings of thecadmium-silver and copper-lead type. These include, and I may employ,the oil-soluble Li, Na, K, Cu, Zn, Mg, Ca, Ba, Sr, Al, Pb, Ni, Co, Mn,Cr, Sn and Fe salts of the phenolic compounds. I particularly prefer toemploy the alkaline earth salts, calcium, barium, magnesium andstrontium, and probably also the aluminum and zinc salts, of thephenolic compounds because of their greater solubility in oil and theirpossibly lower catalytic activity.

My invention, therefore. resides also in alubricating oil containing asmall amount of an oil-soluble metal salt of a phenolic compound eitheralone or in combination with other constituents, for example, thoseadapted to enhance the oiliness or film strength of the oil, or even aneutral common solvent, such as the higher boiling alcohol-ethers,adapted to increase the solubility of the metal salt in the oil.

Also, the invention includes the use of these salts in lubricating oilin the indicated proportions, in combination with small amounts of othertypes of oil-soluble soaps having "detergent" properties in theengine,in proportion sufficient to overcome or greatly retard thedeposition of resinous and varnish-like materials upon piston rings,valves and the like. One type of detergent soap which may be employed inconjunction with the corrosion inhibiting soap described above is theoil-soluble metal sulfonates, preferably the alkaline earth metalsulfonates such as barium, calcium, strontium and magnesium andpreferably calcium sulfonate, or the alkali metal sulfonates such assodium or potassium sulfonate, or the sulfonates of other metals such ascopper, zinc, aluminum, lead, nickel, cobalt, manganese, chromium, tinand iron. Some of these sulfonates are more fully described hereinafterand in my mentioned patent application Serial No. 345,844 filed July 16,1940.

These metallic sulfonates are especially valuable additives to minerallubricating distillates. especially those which are highly parafllnic inof lower V. I., often are desirable.

lubricatingdistillates,suchas60to80V.I.dis-

tillates, or 40 to 60 V. I. distillates or even those tage of thedistillate lubricating oils appears to be that they produce carbon inthe engine which is much less abrasive than that from residual oils suchas the ordinary Pennsylvania bright stock used for lubricating purposes.The distillates also show a lower Conradson carbon value than theresidual type lubricatingoils. These advantages are also obtained whenthe anti-corrosion salts are added, and also when other detergent soapsare employed. The invention extends also to all these aspects. Inaddition, residual type lubricating oils can be used with these soapsfor some uses but ordinarily the carbon formed is of objectionable type.

The term Viscosity index (V. I.) is defined in Chemical andMetallurgical Engineering, vol. 36, No. 10, pages 618-619 (1929). It isan indication of the type of oil, whether more or less paraflinic ornaphthenic, a paraffin base oil being assigned 100 V. I. and certainGulf Coast naphthene base oils being assigned zero V. 1., so that mixedbase oils have intermediate values. Thus, the high V. 1. oils are theso-called highly "paraflinic oils, such as Pennsylvania oils and thosehighly refined with selective solvents such as phenol, aniline, liquidsulfur dioxide, nitrobenzene, furfural, dichlorethyl ether and the like.

The mentioned sulfonate soaps may be used in the indicated oils inamounts in the order of 0.5% to 1.5% as required to accomplish thedesired result. Other types of detergent" soaps, which are used insimilar proportions, are produced from soap-forming fatty acids andmodified fatty acids such as the calcium and magnesium soaps of phenylstearic acid and chlorostearic acids, and from naphthenic acids, rosinacids, modified rosin acids, and synthetic petroleum acids formed by theoxidation of petroleum fractions such as highly solvent-treatedparaffinic type lubricating oil fractions, paramn waxes, petrolatum andthe like. -Other metals may be used for soap production, as heretoforeindicated, where sufllciently oil-soluble soaps are produced.

Where low V. I. oils are used, the mineral lubricating oil employed maybe a California or a naphthenic-type oil which ordinarily contains about0.5% of organically combined sulfur, but may contain as little as 0.15%of such sulfur. Higher sulfur content oils such as those derived fromSanta Maria Valley (California), crude oil containing up to 4% or even5%, for example, 2.75% of such sulfur, are sometimes very desirable.These are all distillates of low Conradson carbon value. This sulfuralso tends to inhibit bearing corrosion and the formation of the acidcondition causing it, as elsewhere herein indicated. With metal salts ofadequate oil solubility, as in the case of the calcium salts of phenoliccompounds containing hydrocarbon side chains attached to the ring, asindicated below, the base may be a well refined parafllnic-type oil.

The advan- The oil-soluble metal salts such as the calcium salts of thephenolic compounds are employed in the lubricating oil in amounts up toabout 3%. but in amounts less than that required to cause an undesirablethickening of the oil, the optimum apparently being from about 0.5% to2.0%.

A specific usable phenolic material of which I have produced the calciumsalt is di-paratertiary-amyl diphenol sulfide, which apparently has theformula:

Alkyl hydroxy phenyl thio ethers of this type are described in theMikeska et al. Patent No. 2,139,766 and other similar compounds andtheir method of preparation are given in Mikeska et al. Patent No.2,139,321.

A phenolic material believed to be kindred to that of the Mikeska et al.Patent No. 2,139,766, is at present obtainable on the market under thetrade-name Paranox which is available from the Standard Oil DevelopmentCompany. This material, apparently, is in general composed of mixedpoly-alkyl poly-phenol sulfides, that is, polyalkyl-substituted hydroxyphenyl thio ethers containing, for example, a thio ether of butyl phenolwhich may be designated as his (2-hydroxy-4-butyl phenyl) sulfide. Thiscommercial product apparently contains various materials of thefollowing general formulas:

R(CcHsOH) S(CcH3OH) R and R CsHaOH) S (CsHzOH) R.S (CeHaOH) R In theseformulas and similar formulas herein S in general indicates one sulfuratom, but in some molecules two or more sulfur atoms may be represented,the major proportion, however, preferably being mono-sulfides; R is analkyl group preferably containing four or five carbon atoms (but maycontain more) which groups may be different for the different componentsof the mixture or may be different for the two or more benzene nuclei inone of the components. R, S and OH may occupy any of the possiblepositions in the benzene rings. The material may contain higher polymerssuch as indicated in the second formula above, and even more extensivelypolymerized materials.

The metal salts of the above described phenolic materials may properlybe considered soaps because of an apparent detergent action. When about1% or between about 0.5% and about 2.0% or 3.0% of such a suitableoil-soluble salt such as the calcium salt is dissolved in minerallubricating oil. it has the combined effect of imparting to theminerallubricating oil where intended for severe service internal combustionengines, some required detergency characteristics and at the same timeof acting apparently as a neutralizing agent or, at least in somemanner, as an agent for preventing the corrosion of bearings such asthose of cadmium-silver and copper-lead alloys.

The invention, therefore, also includes the use of oil-soluble metalsalts of the indicated phenolic type of sulfur-bearing acidic materials,particularly the calcium salts. It also resides in the use of betweenabout 0.5% and about 3.0% of such salts in mineral lubricating oils andespecially between about 1.0% and about 1.5% of the calcium salts of thealkyl polyphenol sulfides or polysulfide materials described, especiallywhere the lubricating oils are for use in Diesel engines or other severeservice equipment.

In practicing this phase of the invention commercially, the salts ofsuitable phenolic compounds such as the calcium salts of dibutyl orother alkyl or mixtures of alkyl phenol sulfides above indicated may beformed without particular difliculty by any suitable procedure, as willbe obvious to the skilled chemist. For example, the calcium salts ofthese compounds may be conveniently obtained by first adding thestarting material to an approximately equal quantity or even greaterquantity of a suitable lubricating oil such as a naphthenic base mineraloil having good solvent properties for the phenolic material and for thesalts to be produced. This oil mixture is then commingled with hydratedcalcium oxide and a small proportion of water, followed by heating toabout 300 F. with agitation for a time sufficient to insureneutralization and dehydration. The resultant mixture is filtered toremove solids such as excess calcium oxide. (calcium content) has beenincreased when desired by first heating only to about 200 F. to 210 F.for a time to insure complete admixture and partial neutralization, themixture being then cooled to 150 F. to 170 F. and a small quantity inthe order of about 3% of 95% alcohol added, and the temperature of thmix then raised to the previously mentioned temperature of 300 F.Another method employed has been to neutralize the alkyl phenol sulfideswith sodium hydroxide and then by metathesis with calcium chloride orthe like, convert the sodium salt to the calcium salt. In preparing fortreatment of the Paranox described above as probably comprising amixture of alkyl phenol sulfides, about 20% of the sulfides shouldappear in about 80% of lubricating oil having good solvent power for thesoap. Otherwise, a greater proportion of lubricating oil is added as itssalt-dissolving power decreases. The above described neutralization toproduce the calcium salts thereof is more or less easily accomplisheddue to the fact that the pure phenolic material has been found to havean acid number of about 98. The other alkaline earth metal salts mayalso be readily produced in a similar manner. In preparing salts ofother metals previously mentioned, the metathesis procedure justmentioned may be preferable as will be readily determined by the skilledchemist. These operations yield concentrates consisting of salt in oil.

These salts are readily soluble in lubricating o'ls in the requiredproportions and yield alkaline solutions. Representative salts thusproduced appear to have the following structural formulas:

and

In preparing Diesel engine lubricating oil according to the presentinvention the salt, or the The ash salt-oil mixture or concentrate, isstirred into an appropriate mineral lubricating oil and solution isefl'ected by agitation, a slight elevation of temperature beingproducedif desired to facilitate the solution operation.

When the calcium salt is dissolved in the lubricating oil to yield inthe final product a salt content in the order of about 1% to 1.5% or inamounts from about 0.5% up to about 3.0%, the detergent action of theresultant lubricating oil is suflicient to overcome or prevent thedeposition of the objectionable amounts of said resinous andvarnish-like materials above mentioned, and at the same time thisquantity of salt is insufilcient to increase substantially the originalviscosity of the base mineral lubricating oil. Not only do the calciumsalts of these alkyl phenol thio-ethers produce such detergency andthereby prevent sticking of rings and valves and the deposition ofvarnish-like coatings, but at the same time they prevent the formationof objectionable corrosive acid conditions which attack materially thehighly corrosion-sensitive alloy bearings of the copper-lead type.

In addition to the general functions of a soap which are imparted to theoil by this calcium salt, the presence of the sulfur in the saltmolecule tends to impart to a non-sulfur-containing lubricating o lextreme pressure characteristics, and the small percentage of actualsulfur present in the salt further acts to impart in itself someanti-corrosive properties.

In addition to the calcium salts of the phenol thio-ethers indicated,other metal salts of the alkylated phenol thio-ether may be employedsuch as those of barium and magnesium and also znc, and aluminum, theimportant requirements being good solubility in the chosen minerallubricating oil, detergent properties and freedom from appreciableviscosity increase when used in detergent quantities such as theindicated range from about 0.5% to 2.0%. Also, these particular metalsappear to possess less undesirable catalytic activity than some of theheavier metals previously mentioned such as lead. Salts of other phenolethers such as alkyl-substituted phenol selenium or tellurium ethers orthe like containing other suitable sulfur substitutes in the etherposition are also wthin the scope of this invention for some uses wherepossessing sufllcient solubility in oil and adequate detergentproperties.

I have also found that amyl phenol can be condensed with formaldehydeunder appropriate conditions to form a viscous polymer in which freehydroxyl groups of the phenolic type are present. By d ssolving thisresinous phenolic material in nine volumes of lubricating oil andsaponifying by heating with an excess of hydrated lime, followed bydehydration and filtration in the manner described above, I have beenable to form the calcium salt of this phenolic res n. When about 1.5% ofsuch a suitable oilsoluble calcium salt was dissolved in minerallubricating oil it was found to possess the required detergencycharacteristics and, at the same time.

acted to prevent the corrosion of bearings of the cadmium-silver andcopper-lead type,

Further, I have found that stearyl alcohol can be condensed with phenol(monohydroxy benzene) in the presence of concentrated sulfur c acid toform a compound believed to be parastearylphenol. The calcium salt ofthis compound has likewise been readily formed in the manner describedhereinabove and a lubricating oil possessing about 0.65% of the calciumsalt of stearylphenol has exhibited the desired detergent andcorrosion-preventing properties.

In the foregoing disclosure, the oil-soluble metal salts of phenoliccompounds have beenpreferred, but it is to be understood that theoil-soluble metal salts of other weakly acidic, non-carboxylic'compoundshaving ionization constants within the range specified hereinabove areequally satisfactory and are within the scope of the present invention.As group examples or other such weakly acidic, non-carboxylic materials,the .phenols, thiophenols, other. enols, oximes, sulfonamides and thelike were previously mentioned.

The following are specific examples in addition to those given above ofsuitable acidic materials from the classes just mentioned, and includearyl and alkyl substituted phenols and others of the classes mentioned.

In these instances the designation of the various groups by m and n isto provide the respective molecules with sufllciently high molecularweights to yield'salts of good solubility. in oil. Where the moleculehas two rings, it appears that the molecular weight of a salt of goodoilsolubility is around 350- or higher, There may be some instanceswhere a salt of as low as 300 molecular weight will be sumcientlyoil-soluble, but such apparently is not true of all cases. In

general the same lower limits of molecular weights has been taken asrepresentative of salts of suitable acidic materials of other chemicalconfiguration. Varying values for m and n also indicate complexity inthe molecules, which appears to be a desirable feature imparting greateroil-solubility. Branching appears to promote oilsolubility. Further,mixtures of different molecules in which the alkyl groups vary appear tohave better oil-solubility than materials representing a singlemolecule. Thus, these materials may contain alkyl groups (or aryl groupswhere indicated) in which n, or m and n combined, may be smaller whenthe molecules otherwise have relatively high molecular weights, andlarger when the molecules otherwise have relatively lower molecularweights. In general it may he said that m and n will have values fromzero to perhaps as high as 20 or possibly higher for molecules otherwiseof low molecular weight, and from zero to perhaps about 10 for moleculesof otherwise higher molecular weight. Where different groups appear inthe same molecule as indicated by the presence of both m and n, thenumber of one will decrease as the other increases at least toward theupper limit, whereby to avoid undesirably high molecular weights.

The following examples of these materials are arranged accordingto'groups above mentioned:

' I. Phenols Mflnohydroxy phenols 1 gone-.0111

. I onmon.

H0 om ..-cmcm).om

(b) Yulyhydrorypbemls 1 OQHI can cntdcm cmcom H CsHn H (Condensationproduct of p-tert. amylphenol and formaldehyde) 2 on. noQ-tzmonm-omcnmom(As in condensation oi oleyl alcohol and phenol) Q iQls (B may representgroups from propyl to deoyl for example) Here, R represents either anaryl group such as or an alkyl group such as amyl, butyl or other groupbetween ropyl and decyl, or an ester group or the like. Also, at eastone B may represent a halogen such as };'li]t0l'lll or other suitableiilm strength or kindred subs uen 6. Products of the type in allprevious examples in which HO OH and the like appear in place of (c)Condensed ring lphenols 1 1. Products oi t e type in (a) an (b) above inwhich (d) Heterocyclic henols l. Compoun of the types in (a), (b), (e)above in which C) 0 Il/o on and the like appear in place 0! II. TIM

An OH group in the phenol compounds of Group I is replaced with SH.

( cn. cm).cn=Non (b) cn,(cm)..o(om)..cm

CHKCHDJIJ CHa(CH|)-. CH=NOH IV. Sulj'onamidea (a) crmom). ommomncn,

omwm). own (Crimea,

crmom). 0,.Nn

V. Imilio n (a) cm(om).omco

n cmwmncm-oo (o) CHI(CHI)I\ VI. Enolc (a) CH;(CH:)-OC=CH(CHl).CH|

crnwm).oH=c cO-(om)..om

' on g Oil-soluble salts of these various materials may be prepared inmanners as outlined above and added in indicated proportions to yieldthe type of product described and claimed. Important requirements aregood solubility of the salts in oil in the proportions required, withoutsubstantial increase in the viscosity of the base oil, and lowionization constants as above defined with consequent freedom fromdevelopment of corrosive conditions in the oil during engine use whichis presumed to be due to the indicated neutralizing character of thesalts which may be termed reserve alkalinity.

The metal salts of the phenols above indicated may be viewed also asmetal oxides or as phenolates, and where they contain sulfur in theether position as in Group 4 under polyhydroxy phenols they may beviewed also either as sulfides or as thio ethers.

The present invention resides also, as has been indicated, in minerallubricating oils containing small amounts in the order of from about0.3% to about 2.0% or 3.0% of an oil-soluble metal salt of a sulfonicacid to insure good detergency, together with a quantity ofapproximately the same order of oil-soluble anti-corrosion metal salt ofhigh molecular weight non-carboxylic weak acid of low ionizationconstant such as those herein described, which weak acid salts are toassist detergency and particularly to avoid development of the mentionedcorrosive conditions. These weak acids include particularly thementioned phenols and thiophenols. The sulfonic acids are described indetail below. The metal sulfonates and the metal salts of the abovementioned weak acids, when present together in a mineral lubricating oilin the amounts indicated above, produce an oil which is noncorrosivc toalloy bearings such as those composed of cadmium and silver or copperand lead. Further, such an oil has a reduced tendency to causedeposition of varnish-like, resinous or carbonaceous materials in thecombustion chambers or on the pistons or piston rings.

The oil-soluble metal sulfonate may be a salt of the so-called mahoganyacids. The sulfonate preferably is in the form of the calcium salt.However, the other alkaline earth metal salts or soaps. such as barium,strontium and magnesium soaps may be employed. Also the alkali metalsoaps are often useful, and sometimes the heavier metal soaps are usefulsuch as the soaps of copper, zinc, aluminum, lead, nickel, cobalt,manganese, chromium and iron. The anti-corrosion salts of the weaknon-carboxylic acids are from acids having ionization constants of 5 10or less and preferably of lxlH or less, such as 1 10- or within therange of 1x10- to 1x10-". The salts may be in the form of lithium,sodium, potassium, copper, zinc, magnesium, calcium, barium, strontium,aluminum, lead, nickel, cobalt, manganese, chromium or iron salts, but Iprefer to employ the alkaline earth metal salts, e. g. Ca, Mg, Sr andBa. 0! this group of weak acid salts, I prefer to use the oil-solublemetal salts of the phenols.

This phase of my invention is particularly novel in that the combinationof salts of weak acids with the salts of the sulfonic acids hasbeneficial effect on the detergent properties of the oil and on anytendency toward development of corrosive conditions in the 011 duringuse, which effect is not obtained when the substances are used bythemselves. This effect can result from the use of smaller combinedamounts of the materials than can be even approximated by the collectiveresults from the separate use of larger amounts of the individualmaterials. Neither alone is sufficiently detergent. This will becomeevident from the examples given hereinafter. This is possibly explainedby a theory that the salt of the weak non-carboxylic acid improves thecolloidal property of the sulfonate in the oil and thereby enhances thedetergency of the sulfonate. Also, the sulfonate may cause improvementin the functioning of the weak acid salt. Although the combination maybe used in any good lubricating oil (including naphthenic base oils--lowV. I. oils), it was found to be unexpectedly satisfactory in oils of ahigh viscosity index (V. I.), for example, especially distillatelubricating oils with a V. I. of to 95, possibly because of theunexpectedly high solubility" or dispersion in this type of oil. Foractivating the anti-corrosion salts, the small proportions of waterheretofore indicated as lying between about 0.002% and about 0.02% areimportant, even if not essential; the lower proportions are commonlyused with the high V. I. oils. For also activating detergent soaps thehigher proportions of water mentioned, e. g. 0.04% or 0.05% to 0.25%,are important.

The sulfonated acidsemployed to prepare the sulfonate additive of thisinvention may be those synthetically produced, as by du Pont ofWilmington, Delaware, and obtainable on the open market, or thoseobtained from the treatment York city. Acids of the latter type. whichare valuable here, are the oil-soluble so-called "mahogany acids.

The mahogany" acids are well known to the industry. They are thosesulfonic acids which are formed when lubricating oil fractions orsimilar petroleum oil fractions are treated with concentrated or fumingsulfuric acid. These socalled mahogany" acids dissolve in the oil phase,whereas the so-cailed "green" acids are the watersoluble sulfonic acidswhich pass into the sludge. The mahogany acids may be recovered bytreatment of the oils with sodium hydroxide to produce sodium sulfonatewhich is removed from the oil solution by means of the addition of analco hol such as ethyl alcohol or propyl alcohol with heating whereuponthe sodium sulfonates pass into the alcohol solution which is separatedfrom the oil, the alcohol being then distilled oil to leave the sodiumsulfonates.

Sulfonates usable here may be sodium or potassium sulfonates, calcium orother alkaline earth metal sulfonates, or sulfonates of the heavy metalsherein mentioned. Calcium is preferred.

Sodium salts of suitable oil-soluble sulfonic acids ofthis type frompetroleum are obtainable from the Sonneborn Company under the trade namePetronate" which contains about 60% sulfonates and about 35% to 40%mineral lubricating oil. These salts, or the potassium salts, sometimesmay themselves be used, at least in some combinations.

In order to obtain the calcium sulfonate from this mahogany acid soap,the sodium or potassium sulfonate is dispersed in hot water and asolution of calcium chloride is added with agitation while maintainingthe mixture near the boiling point of water. The result is the formationof calcium sulfonate in a. sodium chloride and calcium chloride watersolution. The mixture is cooled to coagulate the water-insoluble calciumsoap, the water solution is drawn off, and the calcium sulfonate mass iswashed with water in the cold. In order to eliminate all of the waterand the remaining sodium chloride, from two to three volumes of minerallubricating oil, based on the calcium sulfonate, are added to thecalcium sulfonate mass and the mixture boiled until all of the water iseliminated, the temperature finally raised to about 325 F. or within therange of perhaps 275 F. to 375 F. During this treatment, the calciumsulfonate passes into solution in the oil, the water is driven off andthe residual sodium chloride which crystallizes in the oil from thewater droplets is then removed by filtering the hot oil solution.Incidentally, any other inorganic salts including excess calciumchloride will have crystallized and been removed along with the sodiumchloride. 1

In one instance 900 grams of the sodium salts of oil-soluble petroleumsulfonic acids containing 40% of mineral oil were dispersed in 3000grams of water and brought to a boil. To this was added 225 grams ofcalcium chloride dissolved in 1000 grams of water. The batch wasagitated vigorously. The excess water was then expressed from the massthrown down, and the mass washed with cold water with removal of theexcess wash water. To the washed soap mass 2000 grams of lubricating oilsuch as described herein was added and the batch dehydrated as above.After addearth and heating to about 300' F., the batch was filtered. M

The resultant material was an oil concentrate containing about 0.05%water and about 20% of oil-soluble calcium petroleum-sulfonic-acid soap,which otherwise may be referred to here as a calcium mahogany acid soap,or calcium mahogany soap or calcium sulfonate. This concentrate isliquid at normal temperatures, is free from mineral salts, and, while ithas an increased viscosity over the original oil, it has no typicalgrease-like characteristics, that is, it is free from all gel structuretypical of greases. The soap is contained in the oil in what appears tobe a state of perfect dispersion approximating possibly a true solution,which appears to be neutral and without the presence of anyappreciableacid number. e

For the present salt and soap combination, sufficient of this sulfonateconcentrate will be employed toimpart to the oil a sulionate content ofaround 0.3% to 3%, approximately 1% representing an average use. Thesesalts are readily dispersible in paraflinic base oils (preferablydistiilates) of high viscosity index, as well as in naphthenic baseoils, in proportions larger than required in the final composition. Eventhe'concentrate may be prepared with a high viscosity index oil, e. g.90 v.1.

Where as the sulfonate additive is used primarily for its detergentproperties, the weak noncarboxylic acid salt is added to activate orin-- crease the detergent properties of the sulfonate as well as toimpart resistance to the development of corrosive conditions affectingthe particularly corrosion-sensitive bearings. This second additiveordinarily may be used in percentages somewhat under those for thesulfonate. For example, if 0.8% to 1.5% of calcium sulfonate is used,then about 0.5% to 1%, or apparently sometimes as low as 0.2% or 0.25%of the weak-acid salt, will ordinarily be used. This is especially trueof the phenol salts. In a specific case, 1.2% of calcium sulfonate wasused with 0.7% of the calcium' salt of di-para-tertiaryamyl diphenolsulfide (Paranox) described, in a 90 V. I. lubricating oil distillate.The water content in the 'flnal blend was about 0.004%. This very smallproportion of water serves to activate the neutralizing orcorrosion-preventing characteristic of the phenolic or weak-acid salt.

While the oil-soluble anti-corrosion metal salts described, such as thecalcium salts of the phen olic compounds. may be employed in thelubricating oil with detergent soaps in small amounts from about 0.2% upto about 3%, the optimum of such anti-corrosion salts is apparently fromabout 0.5% to about 1.5%. The proportion is to be less than that whichwill cause any undesirable thickening of the oil in conjunction with thedetergent soap. A specific preferred material of this type usable withthe described sulfonates is the oil-soluble phenolic material just.mentioned which I have produced and described as the calcium salt ofdi-para-tertiary-amyl diphenol sulfide ("Paranox) in which th amyi groupis believed to be para to the hydroxy position of the phenol. Similaralkyl phenol thioether salts may be used. The salts of these materialsmay be considered either as sulfides or thio-ethers, or as metal oxidesor as phenolates or ing grams of a finely ground diatomaceous 75 asethers, as may other similar suitable phenolic salts herein disclosed.=

In preparing lubricating oils according to the present invention, andaccording to this particular form of the invention, the salts and soapsor soap-oil mixtures or concentrates are stirred into appropriatemineral lubricating oils, and solution or dispersion of the salts andsoaps in the oils is eil'ected by agitation, a slight elevation oftemperature, such as around 125 F. or 130 F. being employed if desiredto facilitate the operation. For example, where a "detergent soap of thesulfonate type" is employed in conjunction with an "anti-corrosion saltof the "Paranox type, these salts and soaps will be blended into ordispersed in the mineral lubricating oil in proportion to yield in thefinal product the total desired salt and soap content. Thus, a calciumsulfonate concentrate would be added to yield, for example, 1.2% ofcalcium sulfonate and about 0.7% of the calcium salt of diamyl diphenolsulfide in the final product.

The ratio of the quantity of the phenol salt to the quantity of thesulfonic acid soap may be varied, but preferably approximately orroughly equal quantities of the two compounds are generally used, thatis quantities to yield substantially equal amounts of ash figured asCaSOr.

The proportions of salts and soaps as herein described are insufllcientto increase substantially the original viscosity of the mineral baselubricating oil. The salts and soaps employed in conjunction with oneanother give excellent detergency characteristics to the oil, while thephenol salt itself acts also as an alkaline reserve to prevent theformation of, or neutralize the effects of, the objectionable corrosiveacids which attack detrimentally the highly corrosion-sensitive alloybearing of the copper-lead type. This is especially true when employingthe small amounts of water herein described.

In addition to the calcium salts of the phenol thio-ethers indicated,salts of other metals of the alkylated phenol thio-ethers may be'employed, such as those of barium, magnesium and also zinc andaluminum, the important requirements being good solubility in the chosenmineral lubricating oil, detergent properties and freedom fromappreciable viscosity increase when used in detergent quantities such asthe indicated range from about 0.25% to 2.0% or possibly 3%. Also, thesemetals appear to possess less undesirable catalytic activity than someof the heavier metals such as lead. Salts of other phenol ethers, suchas alkyl-substituted phenol selenium or tellurium ethers or the likecontaining other suitable sulfur substitutes in the ether position, arealso within the scope of this invention for some uses where possessingsufiicient solubility or dispersibility in oil and adequate detergentproperties.

In the foregoing disclosure, the oil-soluble metal salts of phenoliccompounds have been preferred for use along with the sulfonates, but itis to be understood that the other mentioned oil-soluble metal salts ofother weakly acidic, non-carboxylic compounds having ionizationconstants as specified above, are equally satisfactory and are withinthe scope of the present in- V vention.

As specific examples of the preparation of the combination of theinvention and the effect of some of the herein-described materials, thefollowing are presented:

One thousand grams of the above-mentioned oil-soluble sodium sulfonatein 40% oil, known as Petronate, produced by the Sonneborn Company, wasagitated in 4000 cc. water during the addition of 220 grams CaClz in1000 grams water. After complete metathesis, the product was washed andadded to 2000 grams of a propanedewaxed highly solvent-treated highlyparafllnic SAE 30 high viscosity index mineral lubricating distillateoil (about V. I.) together with about 25 grams of lime to insurecomplete neutralization. The mixture was dehydrated at 300 F. andfiltered at 300 F. to give a filtrate Component I which was a dispersionof 600 grams of oil-soluble calcium sulfonate in 2400 grams of oil, 1.e. a 20% concentrate. It contained about 0.05% water.

To prepare the second additive for my composition, 2000 grams Paranox(amylphenol thioether) obtained from the Standard Oil DevelopmentCompany, was mixed with 500 grams lime, 440 ml. 90% isopropanol and 8000grams of the same high viscosity index (90 V. I.) SAE 30 motor oilmentioned in the above example. The mixture 'was agitated for two hoursat 180 F., dehydrated for thirty minutes at 330 F. with 500 grams ofdiatomaceous earth to give Component II consisting of 2000 grams ofcalcium salt of alkyl phenol thioether together with some unreactedalkyl phenol thioether in 8000 grams of oil, 1. e. a 20% concentrate. Itcontained about 0.1% water.

These two preparations were added to a similar high V. I. (90 V. I.)solvent treated SAE 30 lubricating oil in quantities to give acomposition containing 1.2% by weight of calcium sulfonate and 0.7% byweight of calcium salt of tertiary-amyl phenol thioether. The totalwater content was about 0.005%. This composition, on testing in Dieselengines running with a high load, proved to have excellent detergencyproperties. After the usual period of hours, the piston was free oflacquer deposit, and all of the rings were free and in good condition.The corrosion of copper lead bearings was also at a minimum.

However, using a similar high V. I. motor oil to which had been added1.2% by weight in one case and 2.5% by weight in another case thecalcium sulfonate alone, by means of Component I, the products showedrelatively poor detergency action in Diesel engines. The use alone ofabout 2.0% by weight of the described calcium salt of alkyl phenolthioether by means of Com-ponent II, whose active ingredient wasprobably calcium diamyl-diphenol sulfide, in a higher V. I. oil gave acorrespondingly poor lubricant for severe service engines. At the end offorty hours deposits had appeared on the ring lands and the rings werebeginning to show symptoms of sticking, and on the piston skirt aquantity of a varnishlike material was noticeable.

The above two-component composition is illustrative of the variouscompositions which can be made under the above disclosures employingsulfonates and any other weak-acid salt having the reserve alkalinityproperty.

The invention further resides in the use of a small proportion of waterin oils containing one of the aforementioned oil-solublecorrosion-controlling salts, either where such salt is employed alone ortogether with one of the aforementioned detergent" soaps. A small amountof water increases both the efliciency of the oil-solublecorrosion-controlling salts in mineral oil, and also the efllciency ofthe mixtures of oil-soluble corrosion-controlling salts and detergentsoaps in mineral oil. Also a somewhat larger proportion of water, suchas 0.05% to 0.3%, serves to activate the detergent soap and make it moreeflicient. For example, the calcium salt "Paranox (alkyl substitutedphenol sulfide) is more efficient as a corrosion inhibiting agent inmineal lubricating oil when a small quantity of water is present in thecom-position. Again, when the described sulionate is also present, itsdetergency, in a low V. I. oil for example, is much improved by water asindicated. Apparently, this water may be present in the oil containingthese agents, or it may be loosely bound to the agents themselves. Infact, in some cases the water may be bound to the agents in the form ofwater of hydration.

In general it may be stated that lubricating oil containing either thecorrosion inhibiting agent alone or the corrosion inhibiting agent and adetergent, should also contain from about 0.002%

' 0.02% or 0.03%) water to 0.25 or 0.3% water to about 0.02% water, andpreferably between I about 0.04% and 0.01% water, if it is to exhibitmaximum anti-corrosion characteristics. In the examples given in myprior applications, Serial No. 305,496 filed November 21, 1939, andSerial No. 277,677 filed June 6, 1939, and also given herein, a methodfor producing the salt of "Paranox (alkyl phenol sulfide), was describedin which the final salt produced contained ample water to exhibitoptimum anti-corrosion properties when this salt is added to mineral oileither alone or in conjunction with the detergent soaps described above.Thus, a solution containing 80% mineral oil and 20% Paranox (alkylphenol sulfide) is first blended with an equal volume of lubricatingoil. This oil mixture is then commingled with hydrated lime and a smallquantity'oi water, followed by heating to about 300 F. with agitationfor a time to insure neutralization. This resultant mixture is thenfiltered to remove solids such as excess calcium oxide. The saltconcentrates resulting from these operations contain about 20% salt andfrom about 0.1% or 0.2% to about 0.4% water. Providing this oil solutionof calcium salt of alkyl phenol sulfide is blended with a furtherquantity of oil at a temperature of about or not materially higher than130 F. the blended oil produced will contain sufflcient water to obtainmaximum anticorrosion efliciency from this salt.

As has been indicated above it is also desirable that mineral oil whichhas been blended with an anti-corrosion agent (as defined in thisspecification) and a detergent (as defined in this specification), shallhave present a small amount of water to activate or develop the maximumefllciency of the detergent as well as of the anticorrosion agent. Thisapplies also to the action of the detergent soap apart from anyanti-corrosion agent. It is possible that it is immaterial whether thiswater is held in the form of water of hydration by the additives orotherwise held loosely bound to these materials or whetherthe water issimply present in free form.

As has been pointed out the amount of water present in the mineral oilcontaining'the anticorrosion agent, or containing an anti-corrosionagent and a detergent soap, may, for purposes of activating theanti-corrosion agent, vary within the limits of about two-thousandthsper cent (0.002%) to about two hundredths per cent (0.02%) in the finaloil product, and preferably between about four or five-thousandths percent (0.004% or 0.005%) and about ten or fifteenthousandths per cent(0.010% or 0.015%).

In addition, however, I have found that an appreciable increase of thewater content tends furbased on the final product markedly enhances andphenolates as herein described, and apparently produces the optimumefliciency. This detergency improvement seems to be the most pronouncedwhen using the sulfonates as described. Also there is some evidence thatthis water produces the greatest improvement in detergent action of theblended product when the oils used are lubricating distillates of lowviscosity index (e. g. 20 to 40 V. I.), rather than of high viscosityindex oils (e; g. V. I.) even when distillates are used instead ofresidual oils.

The percentagewater content is perhaps best calculated initially uponthe basis 01' the concentrate as initially made and as herein indicated.Normally these concentrates contain in the order 01' 20% soap or salt,and the range of water content will be from about one-tenth per cent(0.1 to about one per cent or more, depending upon whether one or bothagents are to be activated. Where a single soap or salt is employed thewhole water content required may be contained in that concentrate. Wheretwo salts or soaps. are employed, two separate concentrates arepreferably used and separately added. In this case it is possible thatboth concentrates can contain an appreciable proportion of the water orthat one concentrate may be dry or approximately so and the otherconcentrate contain all or nearly all of the water.

The upper limits of the water content are perhaps more easily determinedthan the lower limits. It is ordinarily important to have enough waterto activate'both the detergent soap and the anti-corrosion salt, whichactivation however is to be accompanied by less water than will aifectthe compatibility of either the detergent or the anti-corrosion agentwith the oil. Too much water may in some instance render the detergentor the anti-corrosion agent or both insoluble in the oil or affect theircompatibility with each other. The amount of water therefore should beadjusted to avoid substantial reduction of the compatibility of eitherthe anti-corrosion or detergent agent with the oil, or with each other.The term "compatibility may be defined here as the property of thematerials to blend readily with one another without substantial tendencyto precipitate or cloud. However, mere cloud or slight tendency to gelmay be of no consequence so long as the oil when introduced into theengine contains the necessary proportion of con- I stituents. Engineagitation and engine heat will then adequately distribute and dissolvethe additives. For practical puropses where the detergent soap is to beactivated as well as the anti-corrosion salt, the upper limitconveniently varies apparently from about 0.1% to 0.25% or possibly 0.3%depending upon the detergent soap. Where the soaps will permit morewater, apparently there is no added advantage.

The lower limit of water content from the standpoint of activating onlythe anti-corrosion salt, may in some cases be somewhat awkward todefine. Viewed from the standpoint of the water in a 20% concentrate,rather than from the standpoint of the finished oil, the proportionapparently should be more than a mere detectable trace and should be anamount whose proportion can be determined. In the range of onetenth percent (0.1%), or even as low as fivehundredths per cent (0.05%) the watercontent can be determined. Below that figure measurement is difficultand such amounts also are usually too low for effect. A convenientmethod for water determination is the Karl Fischer method described bySmith, Bryant and Mitchell in the Journal of the American ChemicalSociety, vol. 61 (1939) page 2407.

or course, it is to be understood that in some combinations theindicated lowest permissible percentages do not sufficiently activatethe anticorrosion agent. For example, some detergent soaps, such as thesalts of the oxidation of acids from paraiiinic type compounds, developcorrosive conditions in an engine more readily than do sulfonates.Apparently in the case of these more active carboxylic acid soaps, theanti-corrosion agent needs to be activated more rapidly and more readilythan when using agents which develop corrosiveness not at all or moreslowly, such as the sulfonates. Therefore when the sulfonates areemployed less water is required than where carboxylic acid soaps areemployed. Similarly, if no detergent agent is employed, the onlycorrosiveness that develops apparently is due to that from acidicmaterials formed in the engine merely under engine conditions. Forexample, if the so-called Paranox type of salt is used alone, less waterwill be necessary than when used with carboxylic acid soaps.

Again, from the standpoint of activating only the anti-corrosion salt,it appears that in the case of oils which possess a high viscosity indexor low viscosity gravity-constant (highly parafflnic oils or oils whichhave been heavily treated with solvents such as phenol, dichlorethylether, sulfur dioxide or nitrobenzene), it is usually desirable to useonly a relatively small amount of water. At any rate, this is true where"detergent" type soaps having low tendency toward catalysis of oxidation(such as sulfonates) are used along with the anticorrosion type salts inhigh V. I. oils. For example, where the calcium salt of the alkyldiphenol sulfide (Paranox) and calcium sulfonate are blended with an oilof low viscosity gravityconstant (high V. 1.), about 0.002% to 0.006% ofwater is usually suflicient. (Viscosity gravity constant, V. G. C., isdefined by Hill and Coats in Journal of Industrial and EngineeringChemistry, vol. 20, page 641, 1928.) Again, where detergent soaps ofcarboxylic acids are used with anti-corrosion salts of the phenolic typein low V. I. oils, e. g. 20 V. 1., the higher ranges of water arerequired to activate the anti-corrosion agent. It is not known whetherthe smaller proportions of water may be used under most conditions in anoil of high viscosity index merely because of the character of the oil,and/or its soap content, or whether for some reason the composition canpick up water rapidly enough during engine operation, as by reason ofwater vapor blown past the pistons from the combustion chamber, whichaccession does not occur rapidly enough in the case of low viscosityindex oils, i. e. naphthenic type. Also, the greater the percentage ofphenolic type salt required, the greater also will be the proportion ofwater required in the oil composition. The aspect of water content toactivate the detergent soaps was described above.

A further feature of invention is found in the fact that relativelysmaller proportions of free acidic materials from which the soapsareprepared are sometimes highly beneficial in promoting compatibility ofthe various soaps in the oil concentrates or in the final product. Thismay be, for example, in the order of perhaps as low as two per cent toten per cent or even more based on the soap content. Where weak-acidsalts such as the phenolic type used for anti-corrosion agents areconcerned, no compensating agent is required. This is true, for example,where a Paranox salt oil contains 8% or 10% of free Paranox" based onthe Paranox" salt content, which is especially valuable when used inconjunction with carboxylic acid detergent soaps, e. g. soaps ofsynthetic acids from the oxidation of highly parafiinic petroleumfractions, However, where stronger acids, such as carboxylic acids, areused for the detergent type soaps, any such free acid, as where used toimprove compatibility to facilitate handling for example, will beneutralized by the anti-corrosion agent on blending. Therefore anadditional amount of anti-corrosion agent suflicient to care for thisneutralization must be used.

As to anti-corrosion salts, I have also found that phenolic materialswhose salts may be used either alone or with detergent type soaps suchas the described sulionates, are phenolic materials resulting wherealkyl phenols such as an amyl phenol are condensed with formaldehyde.The water contents required in resultant oil compositions will be thesame, under the different conditions, as described above. The alkylPhenol can be condensed with formaldehyde under appropriate conditionsto form a viscous polymer in which free hydroxyl groups of the phenolictype are present, and appropriate oil-soluble salts such as calciumsoaps canbe produced therefrom. For example, I have manufactured thecondensation product of p-tertiary amyl phenol with formaldehydeemploying both an acid catalyst and a basic catalyst. Where employing anacid catalyst I have used about 82 grams (0.5 mol.) of amyl phenol withfrom about 27 grams to about 49 rams (0.33 to 0.5 mol.) of 37% formalin(formaldehyde) with 2 ml. of 37 of hydrochloric acid. These materialswere combined and refluxed for one hour where the higher molecularproportions of formaldehyde were used and up to three hours where thelower proportions of formaldehyde were used. The refluxing temperatureswere conveniently carried between about 200 F. and 212 F., anyappropriate range obvious to the skilled chemist being suitable. Whenthe condensation product was formed by refluxing as above, a thickliquid, resinous material was obtained when the smaller proportions ofthe formaldehyde were used and a more pasty material when the higherproportions of formaldehye were used. In these cases the resultantliquid or paste as one part was then added to nine parts variously ofSAE 20 and SAE 30 grades of California or naphthenic base minerallubricating oils and high viscosity index '(80 to V. I.) parafllniclubricating oils. These were mineral lubricating distillates. (In somecases, there was added to this mass the water layer from the refluxingopera.- tion, this water being that of the formaldehyde solution.) Tothis mass there was then added 37 grams (0.5 mol.) of hydrated lime andthe batch was agitated for two hours at temperatures ranging between F.and 200 F., and then cooled. In some instances 60 ml. of ethyl alcoholwas then added and the batch further agitated for about two hours at 180F. Where alcohol is used there is less hydrolysis and the calciumcontent is increased. In each instance the temperature and time oftreatment and the nature of the treatment was such as to eifectconversion 01' the phenolic resin into the calcium salt thereof. Inorder to remove completely any unconverted lime and other solvents therewas mixed into the batch a quantity of suitable fllter aid such asground diatomaceous earth (e. 8. "Super-Gel) approximating the amount ofthe hydrated lime employed (about 37 grams), and the batch heated to 300F. and filtered at about that temperature.

Suitable resins were produced in the same manner by employing 2 ml. ofammonium hydroxide containing 28% NH: as the catalyst instead ofhydrochloric acid, the refluxing in these particular cases beingslightly longer, the results apparently being equally satisfactory.

These products constituted concentrates, that is. 10% of the calciumsalt of the phenolic condensation product with 90% of the naphthenicmineral lubricating oil mentioned. These concentrates were dilutable inall degrees with either naphthenic base oils or paraiflnic-typelubricating oils without precipitation of the salt after long standing.A higher salt concentrate can be obtained by using smaller amounts ofoil',

although the larger amounts render, the mass more workable.

The same salts have also been prepared directly by adding the hydratedlime to the original mass, thereby employing the lime as a catalyst.Thus 82 grams of amyl phenol, 328 grams of the mentioned 600 viscositymineral oil and 3'7 grams of hydrated lime were charged into a closedflask,

having a sealed agitator and a reflux condenser,

the phenolic condensation product with the form aldehyde and itsconversion into the calcium salt thereof was effected directly in oneoperation to yield a concentrate containing salt.

Other alkyl phenols than amyl phenols where the alkyl group contains atleast 4 carbon atoms such as butyl, hexyl, octyl, nonyl, decyl andothers of 11 and morecarbon atoms per group may be employed as has beenindicated above. and other metals than calcium, particularly the otheralkaline earth metals and the light metals aluminum and zinc, may beemployed in the formation of the oil-soluble metals salts. These saltsmay be considered either as phenolates or as metal oxides in which therings carry alkyl groups to weight to render them oil-soluble.

rther, I have found that stearyl alcohol can be condensed with phenol(monohydroxy benzene) in the presence of concentrated sulfuric acid toform a compound believed to be parastearylphenol. Salts are prepared inmanner similar to that described above. The metal alcoholates, such asaluminum, zinc, calcium and sodium alcoholate, where the alcoholconsists of a hydroxy group attached to an alkyl, aralkyl, or cycloalkylradical, also have value in use with the sulfonic acid soaps. Thestabilizing efie'cts which these alcohols alone impart to lubricatingoils are described in the Shoemaker et al. Patents insure suflicientlyhigh molecular Nos. 2,057,212 and 2,125,961, but the combination ofthese alcoholates with the metal sulfonates not only increases theinherent detergent properties of the metal sulfonates, but also thealcohols retain their beneficial stabilization characteristics. Thesematerials also may be considered as metal oxides.

As specific examples of the two types of oils used to produce productsof this invention, and examples of the products themselves, those in thefollowing table are furnished. Both oils are distillate oils. The one isa typical Western or naphthenic base oil of low viscosity index (about15 V. 1.), and the other is a high viscosity index oil (about V. I.) ofparafllnlc type such as produced by propane dewaxing a Westernparaflinic and naphthenic distillate (from Santa Fe Springs, California,crude) and then heavily solvent treating the same as with phenol toeliminate the naphthenic and kindred constituents. The paraiflnic typeblend, and also Blend A of the napthenic type, contained enough water toimprove or activate the anti-corrosion properties of the sulfonatebeyond that where the oil was dry. Blend B of the napthenic oilcontained enough water to activate or improve also the detergentproperties of the phenolic salts. Both types of oils, being lubricatingdistillates instead of residual type lubricating oils, had relativelylow carbon residues (below 0.2) and developed only mildly abrasive ornon-abrasive carbon in the engines, as distinguished from typicalresidual Pennsylvania lubricating oils which have Conradson carbonvalues in the order of 0.40 to 0.50 and develop highly and thereforeobjectionably abrasive carbon in the engines.

Lubricating oil specifications Parafilnic type Na phthemc type low v. I.distillate Base Base Blend Blend oil Blend oil A B S. A. 20 20 so so 30glscosity xndextW. I.) 89 89 l5 l8 l4 iscosity gravi y Constant (V. O0.809 0. 814 0.877 0.881 0.881 Gravlty A. P. I. 60 F 29. 5 28.6 20.619.9 19.9 (four p gmft X F 10 10 -10 l0 5 .-0 or 5 5 2 4 4 ViscositySaybolt Uni- M A versal:

At 100F .seconds. 352 385 582 029 045 At 210 F do 54.2 56 55.7 57.4 57.5Fire point C. O. C.F 520 520 415 415 415 Flash point C. O. C F 445 44037 370 375 Calcium petroleum sulfonate (from Petronate).. percent 1.21.2 1.2 Calcium amyl phenol sulfide (from "Paranox") ..d0. 0.725 0.7250. 725 Water... 0. 0.01 0. 0. Conradson carbon rosi' due 0.05 0.12Sulfate ash 0. 45 0. 43 0. 45 Carbon residue plus ash. I 0. 57 lNeutralization No.

alcohol method) i 1 Soaps tend apparently to raise carbon residue to avalue beyond original carbon residue and ash combined.

1 Slightly alkaline.

It is to be understood that these oils are illustrative of the genericinvention and that they are not to be taken as necessarily limitingthereof.

I claim:

1. Lubricating oil comprising mineral lubricating oil and a smallproportion of oil-soluble anti-corrosion non-carboxylic salt of a weaklyacidic organic compound having an ionization constant below about 5 10-between about 0.2 and 3% not substantially increasing the originalviscosity of the mineral oil, containing also between about 0.5 and 3%of detergent soap not substantially increasing the viscosity of the oil,and between about 0.002 and 0.3% of water to activate the anti-corrosionproperties oi the salt.

2. Mineral lubricating oil containing a small proportion of oil-solublesalt of a phenol-thioether as anti-corrosion salt and a relativelysmaller proportion of water to activate the anticorrosion properties ofthe salt.

3. Lubricating oil comprising mineral lubricating oil and a smallproportion of oil-soluble alkaline earth metal salt of a phenylthio-ether between about 0.2 and 3% as anti-corrosion salt notsubstantially increasing the original viscosity of the minerallubricating oil, and between about 0.002 and 0.3% of water to activatethe anti-corrosion properties of the salt.

' fractions.

tergent soap is from oxidation acids from highly 4. Mineral lubricatingoil containing a small proportion of oil-soluble anti-corrosion non-cab.boxylic salt of a weakly acidic organic compound having an ionizationconstant below about 5 l0-, small proportion oi oil-soluble detergentsoap, and a relatively smaller proportion of water not exceeding about0.3% to activate the corrosion-controlling properties of 'tlieanti-corrosion salt.

5. Freely liquid lubricating oil comprising mineral lubricating oilcontaining a small proportion of oil-soluble anti-corrosion salt ofweakly acidic non-carboxylic organic compound having an ionizationconstant below about 5X 10-, a small proportion of oil-soluble detergentsoap of relatively strong acid, and a relatively smaller proportion ofwater not exceeding about 0.3% to activate the weak-acid salt, thecombined salt and soap contents not substantially increasing theoriginal viscosity of the mineral oil.

6. Oil according to claim 5 wherein the anticorrosion salt is analkaline earth metal salt.

7. Lubricating oil' comprising mineral lubricating oil, a smallproportion between about 0.2% and 3% of alkaline earth metal oil-solublecorrosion-controlling salt, of weak non-carboxylic organic acid havingan ionization constant below about 5 10-, between about 0.5% and 3% ofalkaline earth metal oil-soluble detergent soap of stronger acid, andbetween about 0.002% and 0.3% of water.

8. Oil according to claim 7 wherein the anticorrosion salt is salt of adiphenol sulfide.

9. Oil according to claim 7 wherein the anticorrosion salt is thecalcium salt of di-alkyl diphenol sulfide.

10. Oil according to claim 7 wherein the detergent soap is calcium soapof synthetic oxidation acids from a highly parafilnic petroleumfraction.

11. Oil according to claim 7 wherein the salt and soap are calcium saltand soap, the detergent soap is from synthetic oxidation acids fromhighly parafilnic petroleum fractions and the anti-corrosion salt isfrom di-alkyl diphenol sulfide.

12. Oil according to claim 7 wherein the detergent soap is a sulfonate.

16. Oil according to claim 5 wherein the detergent soap is a carboxylicacid soap.

17. Oil according to claim 5 wherein the deparaflinic petroleumfractions.

18. Mineral lubricating oil containing an oilsoluble anti-corrosion saltof a weak non-carboxylic organic acid having an ionization constantbelow about 5X10-, and'an oil-soluble detergent soap of relativelystronger saponifiable organic acid, each salt and soap being present inproportions between about 0.2% and 3% insufficient to impart substantialviscosity increase to the original oil, the composition also containinga small proportion of free organic acid as a solubilizer for the saltand soap and a small proportion of water not exceeding about 0.3%. v

19. Oil according to claim 18 wherein the detergent soap is soap ofoxidation acids of highly paramnic petroleum fractions.

20. Mineral lubricating oil according to claim 18 wherein theanti-corrosion salt is from an alkyl diphenol sulfide.

21. Mineral lubricating oil according to claim 18 wherein thanti-corrosion salt is from an alkyl diphenol sulfide and the detergentsoap is a sulfonate from petroleum.

22. Mineral lubricating oil containing a minor proportion of oil-solublemetal salt of alkylated diphenol thioether and a small amount of waternot exceeding about 0.3% to actuate the salt.

23. Oil according to claim 5, in which the detergent soap is a petroleumsulfonate.

24. Oil according to claim 5, in which the anti-corrosion salt is metalphenate and the detergent soap is a metal sulfonate.

25. Oil according to claim 5, in which the mineral oil is of highviscosity index.

26. Oil according to claim 5, in which the anti-corrosion salt isselected from the class consisting of phenol sulfide, telluride andselenide.

27. Mineral lubricating oil containing a small proportion of oil-solubleanti-corrosion salt of a weak organic non-carboxylic acid having anionization constant below about 5X10- selected from the class consistingof alkylated diphenol sulfide, telluride and selenide and a relativelysmaller proportion of water to activate the anticorrosion properties ofthe salt.

28. Oil according to claim 5, in which the mineral oil is a minerallubricating oil having a low Conradson carbon residue.

CHESTER E. WILSON.

